Buffer mechanism for firearms



A. F. GAHDOS BUFFER MECHANISM FOR FIREARMS l Dec, zo, w49

2 Sheets-Sheet l' Filed Jan. 1o, 1947 Afl-nmz. :u PLI-fami dma HIW Hm Patented Dec. 20, 1949 'ATN T FIC BUFFER MECHANISMv FOR FIREARMS Alonzo F. Gaidos, Redwood City, Calif., assignor to the United -States of America as represented by the Secretary of War Application January 10, 1947, Serial No. 721,332

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 9 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of royalty thereon.

This invention relates to a buier mechamsm -for rearms, more particularly to a combination buierrmechanism and means for rapid detachment of the stock from the firearm, without disturbing the normal position of the buier mechamsm.

This invention essentially comprises a buffer arranged to be surrounded by the stock of the rearm and means for mounting the stock to the receiver of the firearm. The buffer mechanism comprises a tube slidably mounted Within a housing member and a recoil spring contained within the tube to absorb the shock of the recoil forces. The housing in turn is securedto a backplate in such fashion that a ninety degree turn of the buffer mechanism will permit release thereof from the backplate. Detent means is providedA to lock the stock to the backplate.

An object of this invention Vis to provide a combination buer mechanism and stock mounting means for a rearm.

Another object' of this invention is to provide a combination buffer and stock mounting means whereby the stock may be rapidly removed from the firearm, without disturbing. the buier mechamsm.

The specific nature of the invention as well as other obiects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. 1 is a fragmentary longitudinal sectional view of the firearm showing the buffer mechanism in the normal position.

Fig. 2 is a similar View showing the actuator of the firearm in the recoil position against the buffer tube forcing such tube rearwardly to compress the recoil spring.

Fig. 3 is a cross-sectional view taken along the line 3 3 of Fig. 1.

Fig. 4 is a detail exploded perspective view showing the buier mechanism housing with the backplate in position for assembly. v

Fig. 5 is a detail side elevational view of the connector member.

Fig. -6 is a perspective view of the locking spring.

Fig. 7 is a fragmentary top elevational view showing the elements of the buffer mechanism assembled, but without the housing, disclosing 2 the manner in which the locking spring locks the various elements together.

In Fig. 2 there is shown in longitudinal section the rearm embodying this invention. Such lirearm comprises mainly a receiver I having a bracket 'It at the rear end thereof and a butt stock 2 (Fig. 2). Receiver I houses a bolt 3, an actuator 4 and a firearm control mechanism 5. Fire control mechanism 5 is contained within a housing IS having a pistol grip El and comprises a trigger 6, a sear member I having an upwardly projecting arm' 8 adapted to engage actuator 4, as will be later explained, and a trigger spring 9. A safety I U is provided to lock trigger 6 in a safe position. t is desired to point out here that fire control mechanism 5 is fully disclosed in my copending application Serial No. 694,443, led Sept. 3, 1946, now Patent Number 2,482,758, hence need not be further described.

Bolt 3 is slidably contained within receiver I for longitudinal reciprocating movement. Bolt 3 includes a firing pin II which is actuated by a firing pin spring l2. An ejector I3 is provided in the head portion of bolt 3. A vertically disposed bolt stud I4 is provided on top of bolt 3 which engages a suitable cam track I5 in belt feed lever 25 journaled to pin 69 in top of receiver I to actuate the belt feed pawls of the rearm.

Actuator ll is mounted in receiver I for reciprocating movement underneath and parallel to bolt 3. An upstanding vertically disposed lug I'l is provided on top of actuator ll and such lug rests within a suitable notch I8 provided in firing pin I I to effect actuation of firing pin I I. A longitudinal hole I9 is provided in actuator to support a guide rod 20 and a substantial part of hole I9 is counterbored to permit insertion of a driving spring 2| therein. The rear end of guide rod 20 is secured to the buffer mechanism in a manner as will be later described.

While the above forms no actual part of this invention being disclosed in the aforementioned application, however such is included herein as necessary to fully describe the operation and intent of this invention.

The combination buiier mechanism and stock securing means as indicated generally by the numeral 22 comprises a buffer tube 23, a buffer tube housing 24 and a hollow plug 3|. Buffer tube housing 24 is a cylindrical member as shown in Figs. 1, 2 and 5 and an enlarged diameter head portion 26 is provided on one end thereof. On the small diameter portion of housing 24 there are provided a plurality of lugs 2l, somewhat sawy tooth in section, such lugs being annularly disposed about the periphery of housing 24. However, a substantial portion of such lugs 2 are removed as shown in Fig. 5 by splining to permit insertion of housing 24 into a backplate 28 to be presently described. An axial hole 29 .is provided in housing 24 land the head ,portion 26 thereof is recessed and threaded as shown at 3l).

Plug 3| is screwed into threaded recess 36 and such plug is provided with an integral hub `32 which acts as a spring guide. `There 'is also an axial hole 33 in plug 3| which permits a reduced end portion of rod 26 to pass therethrough. ,Such rod is secured to the rear of plug 3| in a manner to be later described. Buffer tube 23 is a cylin-Y drical member provided with an outwardly flared end 34, such end normally resting on the .bottom of recess 36. When buiier tube 23 receives the impact of actuator 4 the flared end 34 of tube 23 is pushed rearwardly into Ithe hollow interior.

of plug 3l.

A helical buifer spring 36 is contained within buffer tube 23 such spring surrounding rod 20 and driving spring 2|, one end being in abutment with plug 3|, hub 32 supporting such end of the spring while the other end of spring 36 abuts the closed end of tube 23. An inwardly turned flange 3l is provided in the closed end of buffer tube 23 to permit passage of rod 2D therethrough.

Backplate 28 comprises a substantially'rectangular plate 38 and a groove39 is provided on opposite edges of plate 3B as shown in Fig. 4 to permit sliding such backplate onto suitable ribs (not shown) in receiver I. An integral cylindrical boss-like member 46 is provided on the rear face v ,of plate 38 and such boss is provided with oppositely disposed lugs 4! for a purpose to be presently described. Boss 4|) is disposed at right angles to the rear surface of plate 38 and an axial hole 42 is provided therein extending through plate 36, such hole being provided with annular grooves 43 corresponding Yto lugs 21 on housing '24. Oppositely disposed splines 45 are provided in hole 42 to permit insertion of housing .24 into backplate 23 whereby such housing may be quickly secured to backplate 28 by a one-quarter lturn thereof to engage lugs 21 with grooves 43 contained within backplate 28.

A cylindrical recess 46 (Fig. 1) is provided in the forward end of stock 2 on the aXis thereof and is counterbored as shown at 41. A cylindrical housing member 48 provided with an enlarged head portion 49 is inserted in recess 46 and fits tightly within counterbore 41 to prevent such member from rotating. An axial hole .50 provided in housing 48 receives the buffer mechanism 22, which includes buffer tube 23, buffer `housing .24 and plug 3|. An annular groove 52 is provided in the interior of venlarged head portion A49 of housing 48 and oppositely disposed notches 5| are provided on the end face of head portion 49 to permit passage of lugs 4| of backplate 28 therethrough. A one-quarter turn of backplate 28 effects engagement of lugs 4| with annular groove 52 to secure such backplate to housing 48.

Housing 24 and plug 3| are preferably locked in a desired alignment to backplate 28 and such is accomplished by a locking member 53 comprising a substantially L-shaped spring-like member. A transverse hole 54 *.(Fig. V6') is provided in the vertically disposed leg 55 of vlocking member 53 and a slot communicating from the bottom of such leg to hole 54 is provided-so that such leg may straddle an rannular groove provided in the extreme rear end of rod 20. The other horizontal leg of locking member 53 extends forwardly across the top of plug 3|, housing 24 and backplate 26 lying within shallow longitudinal grooves lil, l, and recess 'l2 provided in the top of each of the aforementioned members respectively. lThus these members are secured -in proper alignment at all times which facilitates assembly and disassembly thereof from the firearm.

Detent means is provided to lock and position stock 2 to backplate 26. Such means comprises a spr-ing 73 and a plunger 56 horizontally disposed within a suitable recess 5l provided on the top forward end of stock 2. A plurality of gearlike teeth `56 are provided on top of plunger 56 and such teeth cooperate with a pinion-like gear 5S supported by a transverse pin 60 within recess 5l. The forward end of plunger 56 is of slightly reduced diameter and enters a hole 6| provided in backplate 28.

A plunger housing 62 is contained within recess 51 and abuts the rear surface of a stock ferrule 68 provided on the end of stock 2. A transverse hole 65 is provided in ferrule 68 -to permit plunger 56 to pass therethrough and into hole 6| of backplate 28. Thus when plunger 56 projects through hole 65 into hole 6| of -backplate stock 2 is locked against rotational movement to receiver i. Plunger 66 is-readily retracted from hole 6| in backplate 28 by manual rotation of pinion 59. v

With the buier mechanism and stock assembled to the firearm as shown in Figs. 1 and 2, such buffer mechanism is set Ito receive the impact of actuator 4. In Fig. 2 the actuator -is shown in contact'with buffer `tube 23 at the 4end of the recoil stroke. Buffer tube 2,3 has moved rearwardly a substantial amount thereby partially compressing spring 36 contained therein, thus absorbing a substantial part of the recoil forces. Driving spring 2| is likewise compressed on `the recoil stroke of actuator 4. The forces exerted against spring'36 are in `turn transmitted to backplate 28 by means of the connection of lugs 2 with backplate 28. At the completion of the recoil stroke vof actuator 4, driving spring 2l and buffer spring 36 return actuator 4 forwardly whereupon Sear arm 8 engages sear :notch 66 provided in the underside of actuator 4. In such position, however, the buifer ltube 23 no longer bears against the rear end surface of actuator 4.

Stock y2 is readily disassembled from receiver by retracting plunger 56 by means of pinion :59, whereupon stock 2 may be rotated one-quarter of a turn in either direction so that lugs 4| come opposite notches 5| whereby the stock may 'be separated from receiver lIf it -is then `desired to remove the buffer mechanism from backplate 2B, locking member 63 is removed from Yengagement with rod 26 in order that buffer tube 223 and plug 3| may be rotated one-quarter of la turn to bring `lugs 21 opposite the splined openings in backplate 23 whereupon such assembly is readily removed. Spring .36 is easily removed from tube 23 by unscrewing plug 3 l. Itis obvious to those skilled in the art that assembly ;of vsuch components is substantially inthe reverse order of disassembly.

It is obvious therefore lfrom the foregoing description and appended drawings that there is here provided a combination buffer mechanism and stock mounting means which is compact'and provides for ease in assemblage Aof the 'rearm stock to the Ireceiver whereby such firearm .may be quickly taken down for inspection :or for amigas .I claim:

1. In a rearm having a receiver, a reciprocating actuator member, a stock, a buffer mechanism comprising in combination, a backplate adapted to be slidably connected to the receiver, a spring biased buffer tube associated with said backplate being constructed and arranged to absorb the recoil force ofthe reciprocating actuator member, a housing recessed in the stock and adapted to surround said tube, means connecting said housing to said backplate, and detent means mounted in the stock and engageable with said backplate whereby the stock is locked to said backplate.

2. In a rearm having a receiver, a reciprocating actuator member, a stock and a buffer mechanisrn comprising in combination, a backplate adapted to be slidably connected to the receiver, a boss on said backplate, said boss and backplate being provided with a hole therethrough, a hollow housing member adapted to be inserted in said hole, means for releasably securing said housing within said hole, a buffer tube resiliently mounted for limited longitudinal movement Within said housing whereby the recoil force of the reciprocating actuator member is absorbed when such member strikes the forward end of said tube, means for securing the stock to said backplate, and detent means mounted in the stock and engageable with said backplate whereby the stock is locked to said backplate.

3. In a firearm having a receiver, a reciprocating actuator member, a stock and a buier mechanism comprising in combination, a backplate adapted to be slidably connected to the receiver, a boss on said backplate, said boss and backplate being provided with a splined hole therethrough, a plurality of spaced annularly disposed grooves on the unsplined portion of said hole, a hollow housing member adapted to be inserted in said splined hole, said housing having a plurality of annularly disposed lugs on the exterior thereof constructed and arranged to engage said grooves When said housing is partially rotated whereby said housing is secured within said splined hole, a buffer tube slidably mounted in said hollow housing, a recessed plug member secured to said housing, spring means associated with said tube and said plug member adapted to absorb the recoil force of the reciprocating actuator member, means for securing the stock to said backplate, and detent means mounted in the stock and engageable with said backplate whereby the stock is locked to said backplate.

4. In a iirearm having a receiver, a reciprocating actuator member, a stock and a buffer mechanism comprising in combination, a backplate adapted to be slidably connected to the receiver, a boss on said backplate, said boss and backplate being provided with a hole therethrough, a hollow housing member adapted to be inserted in said hole, means for releasably securing said housing within said hole, a buffer tube slidably mounted for longitudinal movement within said housing, said tube having an outwardly ared end adapted to engage said housing, a recessed plug member secured to said housing, resilient means disposed within said tube and said plug member arranged to bias said tube forwardly whereby the recoil force of the reciprocating actuator member is absorbed when Such member strikes the forward end of said tube, means for vsecuring theA stock to said backplate, and detent means mounted in the stock and engageable with said backplate whereby the stock is locked to said backplate.

5. In a iirearm having a receiver, a reciprocating actuator member, a stock and a buffer mechanism, comprising in combination, a back plate adapted to be slidably connected to the receiver, said back plate having a rearwardly disposed tubular member thereon and a hole therethrough to slidably receive a buer tube housing, a radially disposed lug' on the exterior `of said tubular member, a hollow cylindrical housing recessed in the stock, said cylindrical housing having an, enlarged cylindrical head portion, said head portion being provided with an interior` annular groove and a slot on the face thereof adapted to receive said lug on said tubular member, a buffer tube slidably mounted in said buffer tube housing, a recessed plug member secured to the rear of said buffer tube housing, spring means associated with said tube and said plug member adapted to absorb the recoil force of the reciprocating actuator member, said backplate is locked to said cylindrical housing when said tubular member is inserted in said cylindrical housing and rotated thereby engaging said lug with said annular groove, and detent means mounted in the stock and engageable with said backplate whereby the stock is locked to said backplate.

6. In a firearm having a receiver, a reciprocating actuator member, a stock, and a buffer mechanism comprising in combination, a backplate adapted to be slidably connected to the receiver, said backplate having a rearwardly disposed tubular member thereon and a hole therethrough to slidably receive a buier tube housing, a plurality of radially disposed lugs on the exterior of said tubular member, a hollow'cylindrical housing recessed in the stock, said cylindrical housing having an enlarged cylindrical head portion, said head portion being provided with an interior annular groove and a slot on the face thereof adapted to receive said lugs on said tubular member, a buffer tube slidably mounted in said buffer tube housing, a recessed plug member secured to the rear of said buffer tube housing, spring means associated with said tube and said plug member adapted to absorb the recoil force of the reciprocating actuator member, said backplate is locked to said cylindrical housing when said tubular member is inserted in said cylindrical housing and rotated thereby engaging said lugs with said groove, and detent means mounted in the stock and engageable with said backplate whereby the stock is locked to said backplate.

7. In a firearm having a receiver, a reciprocating actuator member, a stock and a buier mechanism comprising in combination, a backplate adapted to be slidably connected to the receiver, said backplate being provided with a hole therethrough, a hollow housing member adapted to be inserted in said hole, said housing having a recess therein, means for releasably securing said housing within said hole, a bufferA tube slidably mounted for longitudinal movement within said housing, said tube having an outwardly flared end adapted to engage the bottom of said recess, a recessed plug member secured within said recess being constructed and arranged to limit the rearward movement of said tube, resilient means disposed within said tube and said plug member arranged to bias said tube forwardly whereby .the recoil force of the reciprocating actuator memberlis absorbed when such, member .strikes the forward end @of said tube, locking means gior ioekingfsaid-lhousing and Aplus,r .to :said baekpiate fin kadiesired position, 'means :for securing the `stock :to vseid -ibaickp-la-te, and deterxt .means mounted in :the stock and engageazble with said Joaekpilate whereby the steek 'is detaehably locked Ato-said baekplate. A y

1B.. The eombinai-tion defined in elaiim 7 wherein said locking :means comprises a leaf-like spring memberhaying e depending portion, said depending portion being. provided with a vslot Lhenein, said plug and housing Lbei-ng each'fprovided with anrexterior longitudinally disposed groeve andjsajd hackp'late havingran exterior reess therein, .said .spring member adapted to lie in .each kof said grooves and :to engage 4said recess whensaidfgrooves ,and recess faire in alignment wherebysaid plug :and housing are locked toV safid hackplaite, and a nod axially mounted within Said tube Aamd .p1-ug, .said rod having an annular groove ion the eariend athereof engageable with Said Slot .in said `depending portion :to removably secure said leaf-like spring Y-merriber thereto.

9, T-,he `combinationdefined in claim l5 where- Ell0 in vsaid deter-it means comprises -a plunger vmann-1i'.- ed within a. recess -in the stoek,said plunger having a rack-like portieri on the periphery thereof, a pinion mounted within said recess and eng/afgfeaoie with said rack portion, `and `resilient Vmeans urging said `-plunger forwardly rinte ensagement with said -baekpla-te whereby the steek -is looked thereto, 'said pinion 'being` provided `to retract said :plunger whereby the stoek may be `removed from said baekplate.

ALONZO F. GAIDOS REFERENCES ,CITED The foi-lowing references are `of record 'in the iiie of this patent:

UNITED STATES PATENTS Number Name Date '1g-128,310 Heinemann Feb. 16, '19'15 1,430,661 YLewis Oct. 3, 1922 #1,755,034 Stange Apr. T5, T930 2335,854 Green Dec. 7, 1943 FQREIGN RATE-NTS Number Oountry Date Germany Nov. `6, 1940 

